无法将浮点数转换为十进制数。 首先将float转换为字符串

Question

I get the following error:

02/08 09:15:45> Decimal price: 0.00

02/08 09:15:45> Decimal price = None

TypeError: Cannot convert float to Decimal. First convert the float to a string

Here is my code:

            s.price = Decimal("%.2f" % (float(request.data['subscription_price'])))
            log('Decimal price: %s' % s.price)
            
            if s.price == Decimal("0.00"):
                s.price = None
                log('Decimal price = None')

Any ideas about what I am doing wrong? I tried a hack to avoid saving a 0.00 in the database via the "if s.price == Decimal("0.00"):" ... to no avail.

Answer 1

If you want to convert float number to Decimal with two decimal places this is working code:

import Decimal
In [10]: a = 7.3656
In [11]: Decimal(a).quantize(Decimal('.01'))
Out[11]: Decimal('7.37')

More info about working with decimal numbers you can find here: http://docs.python.org/2/library/decimal.html

Answer 2

if str(s.price) == str(Decimal("0.00")):
   s.price = None
   log('Decimal price = None')